A developer implements SSR for the Color Organizer. The server renders 5 colors and embeds the HTML in the response. The client bundle loads, initializes Redux with an empty state (no window.__INITIAL_STATE__), and calls render(). The browser console shows:

Warning: Expected server HTML to contain a matching <div> in <section>.

After the warning, the page flashes and shows an empty color list. What is happening and why?